Naruto cannot utilize the "Full Power" of Kyuubi just yet. He still needs to grow in their relationship. The "Full Power" can only be obtain through Jinchuuriki and Bijuu Bond.
Edited: How far are you in the Manga? Technically, what I said, along with @gordo1 and you, of Killer Bee helping him. Naruto has released the Seal upon Kyuubi, but has tamed him to some extent. The Bond is growing as Kyuubi as slowing and secretively given Naruto Chakra throughout the War such as to Naruto via Naruto Clone when fighting Madara and Tobi's rampage with Gedo Mazou/ Jinchuuriki Six Paths of Pain via Edo Tensei.